Study: Fitness Trackers Don’t Accurately Count Burned Calories

Wristband fitness trackers accurately monitor heart rate, but are much less effective in determining calories burned during exercise, a new study finds.

Stanford University researchers assessed seven of the most popular devices as they were used by 29 men and 31 women and found that most were off by only about 5 percent in keeping track of heart rate, National Public Radio reported.

However, they were 20 percent to 93 percent inaccurate in measuring how many calories were burned, according to the findings published in the Journal of Personalized Medicine.

The findings suggest that using these fitness trackers could undermine a health diet, according to Dr. Tim Church, a professor of preventative medicine at Pennington Biomedical Research Center at Louisiana State University who was not involved in the study.

“It’s just human nature. People are checking these inaccurate counts and they think they’ve earned a muffin or earned some ice cream and they’re sabotaging their weight-loss program,” he told NPR.

Church noted that a study published last year found that people in a weight-loss program who also wore fitness trackers lost less weight than those who didn’t wear the trackers. “It’s an instance of no information is probably better than having bad information,” he said.